initial commit

mne/utils/_bunch.py

@@ -0,0 +1,104 @@
+"""Bunch-related classes."""
+
+# Authors: The MNE-Python contributors.
+# License: BSD-3-Clause
+# Copyright the MNE-Python contributors.
+
+from copy import deepcopy
+
+###############################################################################
+# Create a Bunch class that acts like a struct (mybunch.key = val)
+
+
+class Bunch(dict):
+    """Dictionary-like object that exposes its keys as attributes."""
+
+    def __init__(self, **kwargs):
+        dict.__init__(self, kwargs)
+        self.__dict__ = self
+
+
+###############################################################################
+# A protected version that prevents overwriting
+
+
+class BunchConst(Bunch):
+    """Class to prevent us from re-defining constants (DRY)."""
+
+    def __setitem__(self, key, val):  # noqa: D105
+        if key != "__dict__" and key in self:
+            raise AttributeError(f"Attribute {repr(key)} already set")
+        super().__setitem__(key, val)
+
+
+###############################################################################
+# A version that tweaks the __repr__ of its values based on keys
+
+
+class BunchConstNamed(BunchConst):
+    """Class to provide nice __repr__ for our integer constants.
+
+    Only supports string keys and int or float values.
+    """
+
+    def __setattr__(self, attr, val):  # noqa: D105
+        assert isinstance(attr, str)
+        if isinstance(val, int):
+            val = NamedInt(attr, val)
+        elif isinstance(val, float):
+            val = NamedFloat(attr, val)
+        else:
+            assert isinstance(val, BunchConstNamed), type(val)
+        super().__setattr__(attr, val)
+
+
+class _Named:
+    """Provide shared methods for giving named-representation subclasses."""
+
+    def __new__(cls, name, val):  # noqa: D102,D105
+        out = _named_subclass(cls).__new__(cls, val)
+        out._name = name
+        return out
+
+    def __str__(self):  # noqa: D105
+        return f"{self.__class__.mro()[-2](self)} ({self._name})"
+
+    __repr__ = __str__
+
+    # see https://stackoverflow.com/a/15774013/2175965
+    def __copy__(self):  # noqa: D105
+        cls = self.__class__
+        result = cls.__new__(cls)
+        result.__dict__.update(self.__dict__)
+        return result
+
+    def __deepcopy__(self, memo):  # noqa: D105
+        cls = self.__class__
+        result = cls.__new__(cls, self._name, self)
+        memo[id(self)] = result
+        for k, v in self.__dict__.items():
+            setattr(result, k, deepcopy(v, memo))
+        return result
+
+    def __getnewargs__(self):  # noqa: D105
+        return self._name, _named_subclass(self)(self)
+
+
+def _named_subclass(klass):
+    if not isinstance(klass, type):
+        klass = klass.__class__
+    subklass = klass.mro()[-2]
+    assert subklass in (int, float)
+    return subklass
+
+
+class NamedInt(_Named, int):
+    """Int with a name in __repr__."""
+
+    pass  # noqa
+
+
+class NamedFloat(_Named, float):
+    """Float with a name in __repr__."""
+
+    pass  # noqa